Optical communications transceiver modules are used in two-way communication over optical fiber. The optical communications transceiver module includes, in a small package, an optical transceiver circuit including a light emitting element, such as a laser diode (LD), or a light receiving element, such as a photodiode (PD). Also, the optical communications transceiver module includes an optical receptacle portion attached to a case of the small package. An optical fiber can be coupled to the optical receptacle portion to enable communication with an optical communications transceiver module at the other party.
A conventional optical communications transceiver module includes an optical receptacle portion and an optical element device portion.
The optical element device portion contains an optical element, e.g., a light emitting element such as an LD or a light receiving element such as a PD. The optical element device portion is secured to a holder of the optical receptacle portion via an adapter.
The optical receptacle portion includes the holder, a fiber stub, a sleeve, and a sleeve cover. In the fiber stub, an optical fiber is inserted along the central axis. The sleeve has a cylindrical shape and is attached to cover the front end of the fiber stub. The holder holds the fiber stub inside and holds the outer peripheral surface of the sleeve cover at a lower portion thereof. The sleeve cover is secured to the holder by press-fitting or by adhesive bonding so as to cover the sleeve. The sleeve cover is also referred to as a shell.
An optical connector can be coupled to the optical receptacle portion in such a manner that a plug ferrule within the optical connector is guided by the sleeve to bring the end surface of the ferrule and the end surface of the fiber stub into contact with each other while being aligned along the central axis. This brings the optical fiber within the ferrule and the optical fiber within the fiber stub into contact with each other to couple the optical signals.
The sleeve cover 114 of the optical receptacle portion is made of a non-metallic material, e.g., zirconia ceramic material. Other materials often used for the sleeve cover include metal materials such as special use stainless steel (SUS). The sleeve cover is secured by being press-fitted, at a lower portion thereof, to the holder. Some sleeve covers are designed to be secured to the holder by an adhesive. However, in view of tightness of securement, and because of consistency of the tight securement obtained, for example, the technique of securing the sleeve cover to the holder by pressfitting is often employed.
The optical receptacle portion, the sleeve cover is made of a non-metallic material, and therefore the sleeve cover will not act as a noise antenna.